Vending machines typically include devices capable of validating and accepting money like coin changers, bill acceptors, credit card readers, etc. Coin acceptor devices function to authenticate and denominate each of the coins inserted into the vending machine. Known coin detection and validation devices utilize various techniques and methods which include optical size detection and metallic content or characteristic detection. Examples of such coin detection devices are disclosed in U.S. Pat. Nos. 4,625,852, 4,646,904, 5,662,205, 5,673,781, 6,230,870. These patents relate to coin detection, validation and denomination and include some features which, in the general sense, relate to the present invention. All of these patents are assigned to the assignee of the present invention.
Typically, the coin acceptor has one coin inlet funnel for all coin inputs and which directs coins toward a sloped coin track along which are located optical and magnetic sensors to validate acceptable coinage and reject spurious materials. After being sensed for validity and denomination, the coin is directed in a number of directions. Valid coins are directed to coin inventory tubes, used for coin payback, or a cash box. Invalid denominations or counterfeit coins are directed to a coin return chute.
In order to properly sense the validity and denomination of the coin, a serpentine path directs the coin toward the beginning of a stainless steel validation rail. The validation rail will both stabilize the coin and guide it past the validation sensors. The rail combined with an inward lean will maximize coin lean against the sensors.
Coin validation begins once the coin acceptor recognizes a coin is passing by the optical and magnetic sensors. After proper coin validation, a series of decision gates actuated by solenoids will control the proper routing of the coin.
Coins containing holes or transparent portions or containing portions made from dissimilar materials represent a difficulty for prior art coin detectors. Coins with apertures of any kind allow light pass through the coin as the coin rolls past an optical sensors and coins having portions of dissimilar metals cause the magnetic sensors to fail to generate a consistent or expected waveform.
The prior art devices therefore do not address the problem of validating coins made of more than one different material with holes that are symmetrical or non-symmetrical, apertures or rings of transparent material.
Accordingly, it is desirable and advantageous to provide a coin detection device having optical and electromagnetic sensors and associated circuits capable of accurately authenticating and accepting coins of different denominations by measuring the unique characteristics of holes, apertures and transparent rings located on the coin.